The present invention relates to a pneumatic tire with tread blocks, more particularly to a configuration of the block capable of improving the block rigidity without sacrificing the drainage performance.
In the pneumatic tires provided in the tread portion with a block pattern formed by a plurality of blocks, the following methods have been employed in order to increase the rigidity of the blocks to thereby improve the steering stability of the tire and the wear resistance of the tread portion:                to increase the land ratio the block pattern (namely, to form the tread grooves with narrow widths);        to form the tread grooves with shallow depths; and/or        to form the wall surfaces (or side walls) of the blocks with gentle slopes.        
In each method, however, it is inevitable that the tread grooves' volume is decreased. Accordingly, there is a possibility that drainage of the tread grooves, specifically aquaplaning performance, is deteriorated. Thus, the block rigidity and drainage are antinomic, and it was difficult to satisfy both of them.